No colours and no hard edges

[jacdac]

He bought a cup of coffee from the machine and sat, looking through the grimy glass to watch Whalsay emerge from the dawn and the mist. Everything was muted green and grey. No colours and no hard edges. Shetland weather, Perez thought.
Source: Red Bones by Cleeves
Context: Insspect is on the ferry deck, on his way from Lerwick to Symbister, largest fishing village in Whalsay. He is watching the island emerging from the dawn and the mist.

What does edges refer to? his view of the demarcation of the island with the surrounding sea?

Thank you.

 

[heypresto]

Yes, imagine the grimy glass, the low dawn light and the mist all contributing to the softening of the view. Something a bit like this maybe:

 

[dojibear]

What does edges refer to? his view of the demarcation of the island with the surrounding sea?

It is the edges of everything - not just the island/sea line. He even says "everything":

Everything was muted green and grey. No colours and no hard edges.

Here an "edge" means the line between any two areas that are different colors. In a bright light, those edges are seen clearly. In a very dim light they are not seen clearly.

Also, in very dim light color vision does not work. The human eye has 2 kinds of vision receptors. The kind that work in dim light (at night outdoors, for example) do not see color.